Three approaches to validating competencies of vocational education programs in technical and professional schools are examined. Competencies are defined as behavior-oriented and relatively simple, observable behaviors which can be identified and measured by the frequency of occurrence. The three models, which have elements in common, are expert consensus, product assessment, and logical analysis. Using the expert consensus model, competencies are classified into groups having common elements and are validated by submitting questionnaires to specialists who determine which competencies are important to effective job performance. In the product assessment model, the frequency of specific, clearly observable behaviors is noted on checklists through the systematic observation of on-the-job workers. In the logical analysis model, competencies are assumed to be complex constructs rather than objective behaviors. Analysis, inference, and judgment are the techniques used, and conclusions are reasonable assumptions presented as a report or working paper. It is concluded that each of the models is useful, depending on the nature of the competencies to be validated. (MH)